Many electronic devices, such as laptops, tablet computers, smartphones, and the like, use rechargeable batteries to provide power to one or more electronic components. A number of electronic devices use thin film batteries as the power source because of the many advantages it has over other batteries. For example, lithium ion thin film batteries which have a potential high energy density while maintaining a relatively compact configuration.
A lithium thin film battery's performance highly depends on the film of the cathode, among other layers. Current lithium thin film batteries available have a capacity of 2 mAh or less, which is often dictated by the thickness of the cathode file. In many batteries, a LiCoO2 cathode film has a thickness of 10 microns or thinner. One way to increase battery capacity, and thus increase the number of applications the battery can be used for, is to increase the thickness of the LiCoO2 film.
Many disadvantages are associated with thicker films. For example, thicker films may result in film cracking and undesirable crystal structures due to the required high deposition rate for thick films. Film cracking and/or undesirable crystal structure may cause low energy utilization and lithium diffusion rates, which may result in poor battery performance. Such disadvantages significantly limit the film thickness in lithium thin film batteries and consequently, confine the application of thin film batteries in electronic devices.